Preparation of disperse bisanil dyes derived from diaminomalec-nitrile

ABSTRACT

Extremely bright, tinctorially strong disperse dyes derived from diaminomaleonitrile and selected aromatic and heterocyclic aldehydes, and their preparation, useful for dyeing and printing polyester and polyester-cotton blend fibers in yellow to blue shades of generally good fastness properties, which dyes are of the general formula

United States Patent [191 Begland Oct. 14, 1975 [54] PREPARATION OF DISPERSE BISANIL 3,132,140 5/1964 Jaffe 260/240 G DYES DERIVED FROM FOREIGN PATENTS OR APPLICATIONS DIAMINOMALEONITRILE 1,305,327 10/1962 France 260/240 G [75] Inventor: Robert Walter Begland, 1,296,647 6/1969 Germany 260/240 G Wilmington, Del. [73] Assignee: E. I. Du Pont de Nemours and Pnma'y Exammer Auen Cums Company, Wilmington, Del.

57 ABSTRACT [22] Filed: Jan. 3, 1974 1 Extremely bright, tmctorially strong disperse dyes de- PP N05 430,415 rived from diaminomaleonitrile and selected aromatic and heterocyclic aldehydes, and their preparation, [52] s CL 2 0 240 G; 2 0 4 5 E; 26O/566 F; useful for dyeing and printing polyester and polyester- 260/465 D cotton blend fibers in yellow to blue shades of gener- 51 Int. cm C09B 55/00 ally good fasthess Propeflies, which dyes are of the [58] Field of Search 260/240 0, 465 E, 566 F general formula Ar Cl-1=NC(CN)=C(CN)N=CHAr [56] References Cited wherein Ar and Ar are aromatic or aromatic like 1 2 UNITED STATES PATENTS groups, for example, phenyl or pyridyl. 2,388,903 11/1945 Cantrell et a1. 260/240 G 2,930,795 3/1960 Biel 260/240 0 x 9 Claims, N0 Drawings close yellow moncondensation products of such for 3 PREPARATION OF DISPERSE BISANIL DYES DERIVED FROM DIAMINOMALEC-NITRILE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to yellow to blue bisanil disperse dyes prepared from diaminomaleonitrile.

2. Description of the Prior Art Monocondensation products of diaminomaleonitrile with various aldehydes are known in the art. Onoda in Nippon Nogeikagaku Kaishi, 36 (2), 167-72 I962) discloses yellow monocondensation products of diaminomaleonitrile with aldehydes; the products are of the formula wherein Ar is either phenyl, p-dimethylaminophenyl or furfuryl. Robertson and Vaughan in J. Am. Chem. 800., 80, 2691 (1958) disclose yellow monocondensation products of such formula wherein Ar is either phydroxyphenyl, p-nitrophenyl or cinnamyl. Reported attempts to introduce a second mole of the same aldehyde appearto have been unsuccessful and attempts to introduce a second mole of a different aldehyde with the monoanil (Schiff base) resulted in displacement of the aldehyde residue of the original derivative. Such displacement facilely occurred when the second aldehyde possessed a carbonyl carbon atom of greater electron deficiency than the original aldehyde; for example, p-nitrobenzaldehyde benzaldehyde p-hydroxybenzaldehyde (descreasing order of facility of displacement.). Hinkel et al. in J. Chem. 500., 1432 (1937) dis- 5 mula wherein Ar is either phenyl, p-anisyl, salicyl or mbromosalicyl. None of the aforementioned references discloses that the monoadducts of diaminomaleonitrile and aldehydes are useful as dyestuffs for synthetic fibers, especially polyester fibers.

U.S. Pat. No. 2,200,689 discloses a heterocyclic pyrazinocyanine pigment dyestuffs which are obtainable by condensing diaminomaleonitrile with l,2-dicarbonyl compounds, such as diacetyl, glyoxal, benzil, ortho-benzoquinone, acenaphthenequinones, thionaphthenequinones, phenanthrenequinones and aceanthrenequinones, at about lO0-300C. in the presence of a solvent, pyridine and a metal salt. They are described as having good fastness properties.

Linstead et al. in J. Chem. Soc., 91 l 1937) describe a variety of phthalocyanine-type pigments which vary in color from blue to green with increasing molecular weight; they are prepared by treatment of 2,3-

dicyanopyrazines of the formula OBJECTS AND SUMMARY OF THE INVENTION The dye trade is continuously seeking new and better dyes for use in existing and newly developed dyeing and printing systems and for use with fibers, blended fibers and fabrics, which fabrics may, for example, be subjected to an after-treatment (after-dyeing) step, such as the application of a permanent press resin composition, to impart a particularly desirable property to the dyed fabric. Dyes which combine brightness of shade and high tinctorial strength with good application and fastness properties are particularly useful in such systems. 1

Bright dyes are more attractive than dull dyes and offer greater versatility in formulating mixed shades. Commercial disperse dyes for use on polyester and other synthetic and semi-synthetic fibers tend as a class to have rather dull shades. Bright disperse dyes often suffer from poor lightfastness or high cost, or both.

It is an object of this invention to provide yellow to blue disperse dyes. It is a further object to provide dyes which exhibit outstanding brightness of shade and high tinctorial strength and which are generally fluorescent and significantly brighter than known existing disperse dyes. It is a still further object to provide disperse dyes with acceptable fastness to light and sublimation on polyester and polyester-cellulosic blend fibers. Yet another object is to provide economically attractive dyes derived from inexpensive starting materials. A further object is to provide a variety of processes for preparing such dyes.

In summary, this invention relates to bisanil disperse dyes (and their preparation) of the formula Ar -CH- =NC(CN)=C(CN)---N=CHAr wherein each of Ar and Ar is independently selected from 1. benzo(5- and 6-membered)heterocyclic groups containing 0-4 methyl substituents and 2. phenyl, naphthyl, S-membered heterocyclic and 6-membered heterocyclic groups containing O-3 substituents selected from N0 halogen, CN, C alkyl, C alkoxy, OCH -phenyl, phenyl, CF OH, OC alkylene-N( C alkyl C alkylene-Cl NHCONH NHCOA, NHSO- A, SR SO- R NHR NHCOC alkylene-B and -NR R wherein:

a. R is C alkyl or C alkylene-R b. R is C alkyl, C alkylene R or, if Ar or Ar is phenyl, C alkylene attached to a phenyl position which is otho to the position to which the nitrogen is attached;

c. R is CN, halogen, OH, phenyl, C alkoxy, 0C

alkylene-CN, CO A, OCOA, OCONHA or CO C alkylene-OCOA;

d. R is CN, halogen, OH, phenyl, OC alkylene-CN, CO A, OCOA, CO C alkylene-OCOA, A,

phthalimido succinimido, glutarimido, OCOCH=CH CH -CH( OCOA )CH- OA or CH CH( OCONHA )CH OA;

e. A is C alkyl or R f. B is halogen, C alkoxy or R g. R; is phenyl containing O-2 substituents selected from C alkyl, C alkoxy, halogen, N0 CN, C alkylCONH and NR R wherein each of R and R is independently selected from H and C alkyl, with at least one of R and R being C alkyl; and

e is llIkUl, (ulkyl.(2 4 a s-s y y 5- DETAILED DESCRIPTION OF THE INVENTION The bisanil dyes of the above formula can exist in two isomeric forms, the cis arrangement.

and the trans arrangement N=CHAr Furthermore, the dyes can be symmetrical (if Ar and Ar are identical) or unsymmetrical (if Ar and Ar are different). The dyes can be prepared by condensing diaminomaleonitrile with the aldehydes Ar CHO and Ar CHO as hereinafter described, Ar CHO and Ar CHO being the same or different. The present invention also relates to additional processes for preparing the heretofore defined symmetrical and unsymmetrical, cis-and trans-bisanil dyes.

Diaminomaleonitrile is generally referred to as HCN tetramer since it is available in low yields from the base catalyzed tetramerization of HCN as shown in US. Pat. No. 2,499,441. Tetramerization of HCN to diaminomaleonitrile also occurs in the presence of a catalytic amount of a basic catalyst and at least one of the cocatalysts diiminosuccinonitrile or cyanogen as shown in US. Pat. No. 3,629,318. Tetramerization of HCN in a aprotic solvent, such as dimethylsulfoxide, in the presence of a catalyst, such as sodium cyanide, at 607()C. at atmospheric pressure, as shown in US. Pat. No. 3,704,797, provides yet another route to diaminomaleonitrile, such a procedure also is described in Chemical Week, July 12, 1972, page 36 and in European Chemical News, Mar. 2, 1973, page 20. Diaminomaleonitrile also can be prepared from diiminosuccinonitrile which itself is preparable, ac-

cording to J. Org. Chem., 37, 4133 (1972), in high yield by the base catalyzed addition of HCN to cyanogen.

'Diiminosuccinonitrile can be converted by chemical -.reagents to diaminomaleonitrile, for example, by reaction thereof with HCN as shown in US. Pat. No. 3,564,039. Diaminomaleonitrile also can be prepared by reaction of diiminosuccinonitrile with hydrogen in the presence of a Group VIII transition metal hydrogenation catalyst as shown in US. Pat. No. 3,551,473.

The yellow to blue unsymmetrical bisanil disperse dyes can be prepared by condensing 1 mole of diaminomaleonitrile with 1 mole each of different aryl aldehydes Ar CHO and Ar CHO. Symmetrical bisanil dyes can be prepared by condensing l mole of diaminomaleonitrile with 2 moles of a single aryl aldehyde.

Examples of substituted aryl aldehydes, Ar CHO and/or ArCHO, which are useful in the preparation of the bisanil dyes are given in Table I.

TABLE I 4-[ N,N-bis( methyl )amino benzaldehyde 4-bromo-2,2-diisopropylbenzaldehyde 4-[ N,N-bis( n-propyl )amino l-2-methylbenzaldehyde 6-formyl-N-( methyl )-2,2,4,7-tetramethyl-l ,2,3,4-tetrahydroquinoline -bromothiophene- 2-carboxaldehyde 4 N-ethyl-N-( 2-methoxycarbonylethyl )amino 1 -2- methylbenzaldehyde 4 N-( 2-butoxycarbonylethyl )-N-ethylamino ]-2 methylbenzaldehyde 4 4-ethylcarbonylamidobenzaldehyde N-methylindole-3-carboxaldehyde 4-thiomethoxybenzaldehyde 4-thio-n-butoxybenzaldehyde 4-thiomethoxynaphthaldehyde 4-phenylsulfonylbenzaldehyde 4-methylsulfonylbenzaldehyde 4-thio-( 2 -hydroxyethoxy )benzaldehyde hyde 4-(N-cyanoethyl-N-methylamino)benzaldehyde 4-chlorobenzaldehyde 2,6-dichlorobenzaldehyde 2-nitrobenzaldehyde 3-nitrobenzaldehyde 4-nitrobenzaldehyde 4- N,N-bis( ethyl )amino] benzaldehyde 4-[N,N-bis(ethyl)amino]-2-hydroxybenzaldehyde 3-hydroxybenzaldehyde 2-hydroxybenzaldehyde 4-hydroxybenzaldehyde 4-[N-cyanoethyl-N-ethylamino]-2-methylbenzaldehyde 4- N ,N-bis( hydroxyethyl )amino] benzaldehyde 4-[ N ,N-bis( cyanoethyl )amino ]benzaldehyde 4- N ,N-bis( n-propyl )amino benzaldehyde 3-chloro-4-hydroxy-S-methoxybenzaldehyde I 4-chloro-3-nitrobenzaldehyde 5-chloro-2-nitrobenzaldehyde i 3,4-dibenzyloxybenzaldehyde 3 ,S-dibromosalicylaldehyde 3,5-di-tert.-butyl-4-hydroxybenzaldehyde 4' 2-( diethylamino -ethoxy benzaldehyde 2,S-dihydroxybenzaldehyde 3,4-dihydroxybenzaldehyde 2,3-dimethyl-4-methoxybenzaldehyde 2,5-dimethyl-4-methoxybenzaldehyde 2,4-dimethylbenzaldehyde 2,5-dimethylbenzaldehyde 2-ethoxybenzaldehyde 4-ethoxybenzaldehyde v 3-ethoxy-4-hydroxybenzaldehyde 4-cyanobenzaldehyde 4 -acetamidobenzaldehyde 2-methoxybenzaldehyde 3-methoxybenzaldehyde 3-benzyloxybenzaldehyde benzalde- 4-benzyloxybenzaldehyde 4-biphenylcarboxaldehyde 5-bromo-2-methoxybenzaldehyde 2-bromobenzaldehyde 3-bromobenzaldehyde 5-bromosalicyaldehycle 5-bromovanillin[ S-bromo-4-hydroxy-3-methoxybenzaldehyde] 5-bromo-3,4-dimethoxybenzaldehyde 6-bromo-3,4-dimethoxybenzaldehyde 2-( 2-chloroethyl )benzaldehyde 2-chloro-6-fluorobenzaldehyde 4-ethoxy 3-methoxybenzaldehyde 3-ethoxysalicylaldehyde 3-fluoro-4-methoxybenzaldehyde 3-fluorobenzaldehyde 4-fluorobenzaldehyde 3-hydroxy-4-methoxybenzaldehyde 2-hydroxy-4-methoxybenzaldehyde 2-hydroxy-S-methoxybenzaldehyde 4-hydroxy-3-methoxybenzaldehyde (vanillin) 2-hydroxy- 1 -naphthaldehyde 4 {N- 2-( benzoyloxyethoxycarbonyl )ethyl -N- methylamino} benzaldehyde 4-( N-cyanoethylamino )-3-n-butylbenzaldehyde 4'-[N,N-bis(ethyl )amino]-2'-( 3-methoxypropionamido )benzaldehyde 2-acetamido-4-( N-cyanoethyl-N-ethylamino )benzaldehyde 2 -butyramido-4 N-cyanoethyl-N-( 2-methoxycarbonylethyl )amino]benzaldehyde 2 3-chloropropionamido )-4' N-phenethylN-npropylamino1benzaldehyde 2 -acetamido-4-[ N-( 2-methoxycarbonylethyl- )amino '-methoxybenzaldehyde 4 N,N-bis( ethyl )amino ]-5 -methoxy-2 3-methylbenzamido )benzaldehyde 2'-chloroacetamido-4-[N,N-bis( ethyl )amino]-5 methoxybenzaldehyde 2 3-chlorobutyramido )-4 N ,N-bis( cyanoethyl- )amino ]-5 methoxybenzaldehyde 2 '-acetamido-4 N,N-bis( 2-acetoxyethoxycarbonylethyl )amino -5 '-methoxybenzaldehyde 4 N,N-bis( 2-acetoxyethyl )amino ]-2 2- chlorobenzamido )-5 -methoxybenzaldehyde 2-acetamido-4-[ N-(2-acetoxyethyl )-N-cyanoethylamino -5 '-methoxybenzaldehyde 4 N-cyanoethyl-N-ethylamino1-5 -methoxy-2-( 4- nitrobenzamido )benzaldehyde 4-[ N-( 2-methoxycarbonylethyl )-N-methylamino]- benzaldehyde 4 N ,N-bis( 2-acetoxyethyl )amino -2 -methylsulfonamidobenzaldehyde 4-[ N-( 2-acetoxyethyl )-N cyanoethylamino]-2 phenylsufonamidobenzaldehyde 4 N,N-bis( 2-acetoxyethyl )amino -5 '-methoXy-2 methylsulfon amidobenzaldehyde 4 N-ethyl-N-( 2-succinimidoethyl )amino -2 methylbenzaldehyde 4 N-ethyl-N-( Z-phthalimidoethyl )amino ]-2 methylbenzaldehyde 4'-[ N-cyanoethyl-N-( 2-succinimidoethyl )aminoj-2 methylbenzaldehyde 4'-[ N-ethyl-N-( 2-glutarimidoethyl )amino]-2- methylbenzaldehyde 6-formyl-N-( ,B-phenylcarbamoyloxyethyl )-2,2,4,7-

tetramethyll ,2,3,4-tetrahydroquinoline 6-formyl-N-cyanoethyl-2,2,4,7-tetramethyl-1 ,2,3,4-

tetrahydroquinoline 6-formyl-N-( B-acetoxyethyl )-2,2,4,7-tetramethyll ,2,3,4-tetrahydroquinoline 6-fo'rmyl-N-( B-benzoyloxyethyl )-2,2,4,7-tetramethyl-l ,2,3 ,4-tetrahydroquinoline 4'-[ N,N-bis( 2-cyanoethylethoxyethyl )amino]-2 methylbenzaldehyde 2 -acetamido-4 N-( 2-cyanoethylethoxyethyl )-N- ethylamino benzaldehyde 4-[ N-ethyl-N-( 2-methylsulfonylethyl )amino]-2- methylbenzaldehyde 4 N-cyanoethyl-N-( 2-phenylsulfonylethyl )amino benzaldehyde 4 N-cyanoethyl-N-( 2-methoxyethylamino1benzaldehyde 4 N-ethyl-N-( 2-propionoxyethyl )amino -2 methylbenzaldehyde indole-2-carboxaldehyde N-ethylindole-3-carboxaldehyde N-( 2-aeetoxyethyl )indole-3-carboxaldehyde thianaphthene-2-carboxaldehyde thianaphthene-3-carboxaldehyde 8 4,S-dibromothiophene-2-carboxaldehyde 4-bromothiophene-2-carboxaldehyde thiophene-3-carboxaldehyde 5-[N,N-bis(ethyl)amino]indole-3-carboxaldehyde 5-[N,N-bis(ethyl)amino]thiophene-2-carboxaldehyde 5- N,N-bis( methyl )amino l ,3 ,4-thiadiazole-2-carboxaldehyde 5-[N,N-bis(ethyl)amino]-1,4-thiazole-2-carboxaldehyde 4-bromofuran-2-carboxaldehyde pyridine-N-oxide-3-carboxaldehyde The aldehydes listed above are either commercially available or can be prepared by well known prior art procedures, such as the Vilsmeier reaction using dimethylformamide, phosphorus oxychloride and the appropriate substituted aryl compound.

Further to the above, the aryl aldehydes can be modified by the incorporation of sulfonic acid groups (SO H) to provide, when condensed with diaminomaleonitrile as described herein, acid dyes for potential use on nylon. Similarly,incorporation of basic groups (N (alkyl) can provide cationic dyes having potential utility on polyacrylonitrile and acid-modified polyester and polyamide fibers. v

The symmetrical dyes, that is, bisanil dyes of the above formula wherein Ar and Ar are the same, can be prepared in one step by condensing 1 mole of diaminomaleonitrile with 2 moles of an aryl aldehyde, in the presence of an acidic catalyst, in an organic solvent, at l50C., while continuously removing the water formed during the reaction either by azeotropic distillation or by the action of a dehydrating agent, such as phosphorus pentoxide or dicyclohexylcarbodiimide. Preferred catalysts in the condensation include sulfuric acid, polyphosphoric acid and p-toluenesulfonic acid. Organic solvents, such as acetonitrile, tetrahydrofuran, dimethylformamide, hexamethylphosphoramide, dimethylacetamide, toluene, xylene, benzene and monochlorobenzene are equally useful. After cooling the reaction mixture to room temperature, the precipitated bisanil dyestuff can be isolated by filtration.

It has been discovered that condensation of 2 moles of 4-[N,N-bis(ethyl)amino]benzaldehyde and 1 mole of diaminomaleonitrile at 50-55C. in -hexamethylphosphoramide containing sulfuric acid as catalyst, in the presence of phosphorus pentoxide to remove the water of reaction, over a 6 hour period, provides the bright, fluorescent, red cisbisanil dye N,N'-{4-[N,N- bis(ethyl )amino benzylidene} diaminomaleonitrile having the structure geometry about the central carbon-carbon double bond is evidenced by the large observed dipole moment (14.6 D) of this dye. This result correlates well with the The low dipole moment of 3.2D on this product supciencies in application properties on polyester when compared to the bisanil. The monoanils, in general, also do not exhibit the fluorescence and brightness which are characteristic of the bisanil derivatives of diaminomaleonitrile. Subsequent condensation of the aforesaid monoanil (1 mole) with 2 moles of 4- chlorobenzaldehyde in benzene, in the presence of a catalytic amount of piperidine, at 7580C., while continuously azeotroping water over a six-hour period, provides, after removal of solvent, a 40-50% yield of the trans-unsymmetrical bisanil N-{4-[N,N-bis(ethyl- )amino]benzylidene}-N'-(4-chlorobenzylidene)- diaminomaleonitrile having the structure ports the structure assignment. Reaction times of up to about four .hours at ll5l20C. generally are adequate for obtaining substantially trans isomer. Upon cooling to room temperature, the trans-bisanil crystallizes and can be isolated from the acid medium. Yields of 60-75% of high purity symmetrical trans-bisanils can be obtained by this procedure. A similar result can be obtained by condensing 1 mole of the monoanil of diaminomaleonitrile with 1 mole of an aryl aldehyde under similar conditions to those described above.

The unsymmetrical bisanil dyes, that is, bisanil dyes prepared from diaminomaleonitrile and two different aldehydes, can be prepared in stepwise fashion by monocondensation of 1 mole of a first aryl aldehyde with 1 mole of diaminomaleonitrile to provide the yellow monoanil derivative. The monocondensation is preferably run in an organic solvent, such as tetrahydrofuran, acetonitrile or benzene, for up to about four hours, at the boiling point of the solvent, in the presence of an acidic catalyst, such as sulfuric acid. The resultant yellow monoanil (lmole) is'then treated with '2molesof a different aryl aldehyde in an organic solvent in the presence of a secondary or tertiary amine catalyst, while azeotropically removing the water formed in the condensation. Preferred amine catalysts are piperidine and triethylenediamine. No condensation occurs in the absence of catalyst. Useful organic solvents include monochlorobenzene, acetonitrile, dimethylformamide, isopropanol, dichloroethane, toluvene and benzene, the latter being most useful. By way i of example of the stepwise condensation, diaminomaleonitrile (lmole) is condensed with 4- [N,N-bis(ethyl)amino]benzaldehyde (1 mole) in tetrahydrofuran, in the presence of sulfuric acid, at 6065C., for 3 hours; a high yield, for example, 80-90%, of the yellow monoanil N- {4-[N,N-bis(ethyl- )amino]benzylidine}diaminomaleonitrile is obtained. This intermediate monoanil possesses inherent defi- When the amount of basic catalyst is less than 0.50 mole per mole of monoanil, the trans-unsymmetrical dye is contaminated with the cis-unsymmetrical dye and both the cis and trans forms of the symmetrical adduct N,N-{4-[N,N-bis(ethyl)amino]benzylidene}diaminomaleonitrile. The latter derivative is believed to be formed by initial hydrolysis of N-{4- [N,N-bis( ethyl )amino ]benzylidene} -N'-(4-chlorobenzylidene)diaminomaleonitrile to N-(4-chlorobenzylidene)diaminomaleonitrile and 4-diethylaminobenzaldehyde, followed by subsequent reaction of the latter aldehyde with the starting monoanil N- {4-[N,N-bis- (ethyl )amino ]benzylidene} diaminomaleonitrile. The ratio of cis and trans products obtained does not change with longer reaction times, for example, up to about 18 hours. However, when the condensation is carried out with an increased amount of basic catalyst, for example, 0.50 mole of catalyst to one moleof monoanil, only the trans-symmetrical and trans-unsymmetrical bisanils are formed. Using larger amounts of aryl aldehyde, for example, greater than 2 moles per mole of monoanil, or using other solvents does not substantially alter the product.

The major drawback of the above-described two-step process for preparing unsymmetrical bisanils of diaminomaleonitrile is that, under the reaction conditions, the product mixtures contain both symmetrical and unsymmetrical dyes. Due to the plurality of prducts capable of being formed by this process, the transunsymmetrical dyes are generally obtained only in moderate yields and complex separation methods usuferred adducts herein) is illustrated by the following general scheme:

This four-step synthesis involves an initial condensation of 1 mole of diaminomaleonitrile with a first aryl aldehyde to give the monoanil adduct. In practice, any organic solvent can be used in this initial step, ketones and aldehydes which can react with diaminomaleonitrile being an exception. It is not necessary to have the diamonomaleonitrile in solution. Solvents which can be used in this condensation include tetrahydrofuran, ethyl Cellosolve, dimethylformamide, methanol, ethanol and mixtures thereof. A useful temperature range is 208()C.; however, a temperature of 25-30C. is preferred and provides the best yield and quality of product. Reaction times of about 4-17 hours can be employed. Acid catalysts, such as sulfuric acid, hydrochloric acid, p-toluenesulfonic acid and trifluoroacetic acid, can be used. The monoanil can either be isolated or the reaction mixture containing same can be used in the next step.

Reduction of the monoanil, for example, with sodium borohydride, gives the N-benzyldiaminomaleonitrile derivative in high yield. Reduction of the monoanil adduct is a critical feature of the improved process in that it precludes the formation of undesirable mixtures during the subsequent condensation with Ar- CHO (as was the case with the abovedescribed two-step process). Preferably, an organic solvent is present during the reduction step; included among the preferred solvents are tetrahydrofuran, methanol, ethanol and ethyl Cellosolve, the latter being especially preferred. The addition of sodium borohydride provides an exothermic reaction and external cooling is necessary to keep the reaction temperature within the preferred -35C. range. Above 35C. the product obtained is of poor quality. The sodium borohydride normally can be added over a -40 minute period while still maintaining the temperature below 35C. Other reducing agents, such as lithium aluminum hydride and lithium borohydride, can also be used. The amount of reducing agent should be at least 0.50 mole per mole of monoanil to obtain complete reduction. The reduced monadduct can be used without further purification in the next step of the reaction sequence. The reduction works best when at least some alcoholic solvent is present in the reaction mixture. Thus, the initial condensation of diaminomaleonitrile with Ar CHO in tetrahydrofuran (THF) to give the monoanil, as previously de- V scribed, followed by addition of methanol to the THF reaction mass and reduction of the monoanil with sodium borohydride, provides high yields of reduced monoadduct. In addition, by carrying out the initial condensation reaction at 2530C. rather than at or above the boiling point of tetrahydrofuran (65-66C.), for example, at C., and by keeping the subsequent reduction temperature below 25C., excellent yields, for example, greater than of theory, of the reduced monoadduct can be obtained.

Condensation of 1 mole of the reduced monoadduct with 1 mole of a second aryl aldehyde Ar CHO provides the monoreduced bisadduct. This step can be carried out with the same solvents and acidic catalysts used in the initial monocondensationstep. However, best results are obtained when a solvent such as methanol or ethanol is used. In such a solvent the monoreduced bisadduct is very insoluble and precipitates as formed. Room (ambient) temperature (ZS-30C.) is preferred in this step for maximizing purity of product; higher temperatures cause the product to darken considerably.

In order to obtain bisanil dyes having a red shade it is necessary, in many cases, to have a dialkylamino group on at least one of the aromatic rings. It is preferred to add the appropriate dialkylaminobenzaldehyde as the second aryl aldehyde rather than as the first aryl aldehyde since the monoanil formed from such an aldehyde is, in some cases, not reduced cleanly by sodium borohydride.

Oxidation of the monoreduced bisadduct in the final step of the four-step process with an oxidizing agent in an organic solvent provides the desired unsymmetrical bisanil dye accompanied, in some cases, by the colorless isomeric 2,3-dicyanoimidazole as shown in the aforesaid equations. The oxidation proceeds readily in tetrahydrofuran, acetonitrile, benzene, ethyl Cellosolve and acetone. However, in these solvents a large amount of imidazole is usually formed. Preferred solvents which give the bisanil dye and little or none of the isomeric imidazole are dimethylformamide, dimethylacetamide, dimethylsulfoxide, hexamethylphosphoramide and N-methylpyrrolidone. Oxidation at room (ambient) temperature (2530C.) is preferred over elevated temperatures. Oxidizing agents that can be used include the nickel oxides, MnO PbO I N0 dichlorodicyanoquinone and chloranil. Manganese dioxide gives the best yield and purity of dye and is preferred. In particular, carrying out the reaction with manganese dioxide in dimethylformamide at 2530C.

filtering to remove insoluble manganese oxides, after 5 which isopropanol is added to the filtrate and the precipitated solids are filtered off and washed with isopropanol; the precipitate is the desired bisanil dye.

Alternatively, in order to eliminate tetrahydrofuran from the above procedure, the reaction mass (after oxi- 1O dation) is poured into water and, after acidification, hydrogen peroxide or sulfur dioxide is added thereto to dissolve the manganese oxides. The resultant mixture is then filtered and the crude dye thus obtained is washed thoroughly with isopropanol. The latter modification l5 eliminates both the expensive tetrahydrofuran solvent and the tedious removal of the insoluble manganese salts, thus providing for a more economical process.

The geometry about the central carbon-carbon double bond of the bisanil prepared by the four-step pro- 20 cess is exclusively trans as evidenced by measurement of the dipole moment. Thus, the preferred four-step process affords a high yield, for example, 70-80% overall from diaminomaleonitrile, of unsymmetrical transbisanil dyes uncontaminated with the cis isomer or the 25 isomeric imidazole.

The symmetrical bisanil dyes previously discussed can also be prepared by the aforesaid four-step process but they are more advantageously prepared in good 3 CH C 14 yield by the one-step process previously described.

As still another example of a process which can be employed herein is a two-step process by which can be prepared symmetrical or unsymmetrical bisanil dyes, and particularly such dyes which have a predominantly trans configuration. This process comprises heating diaminomaleonitrile in dimethylformamide under acidic conditions, preferably provided by sulfuric acid, with a molar equivalent of a first aryl aldehyde Ar CHO to produce a monoanil and then, employing the monoanil thus produced in place of diaminomaleonitrile, repeating the procedure with a molar equivalent of either the first aryl aldehyde Ar CH'O or a second aryl aldehyde Ar CHO that is different from the first aryl aldehyde to produce either the symmetrical or unsymmetrical bisanil dye. The reaction times are very short, usually 10-30 minutes, and water produced during the condensations need not be removed to facilitate formation of the desired product. Although dimethylformamide is the preferred aprotic solvent, other solvents are useful, for example, dimethylacetamide, hexamethylphosphoramide, dimethylsulfoxide and N-methylpyrrolidone. The condensations are carried out in a temperature range of l40C. to the boiling point of the solvent. The preferred range is l40-l50C. Acidic catalysts, other than sulfuric acid, which are useful in pro- -viding acidic conditions include hydrochloric acid, p-

toluenesulfonic acid and trifluoroacetic acid.

Preferred symmetrical bisanil dyes herein include:

Preferred unsymmetrical bisanil dyes herein include:

The crude wet dye from any of'the above processes is conveniently converted into a commercially usable form by mixing the crude dye, for example, 10 parts on a 100% basis, with about 2.5 parts of a lignin sulfonate dispersant and water in a colloid or sand mill. Milling is continued until a fine, stable aqueous dispersion or paste is obtained, that is, until dye particle size is reduced to approximately one micron (average size).

Both the symmetrical and unsymmetrical bisanil dyes possess high tinctorial strengths and provide, on polyester, extremely bright, fluorescent yellow to blue dyeings having generally good fastness to sublimation and moderate fastness to light. These dyes are especially useful for dyeing and printing polyester where bright shades are desired. Because of the chemical versatility inherent in the preparative methods disclosed herein and beeuase of the very high tinctorial strengths and breadth of shades obtainable, the bisanil dyes can be used in such a way as to suppress very undesirable coloration features without paying a color value penalty.

The bisanil dye can be applied to polyester fibers, either alone or in cellulosic blends, by an aqueous procedure, preferably under pressure, or by padding the fibers with an aqueous dispersion of the dye followed by dry heat (for example, Thermosol) fixation. Such dyeing procedures are widely used in the trade. The bisanil dyes are also useful for dyeing and printing polyester fibers, and their cellulosie blends, preferably employing ,a fabric which subsequently receives a durable press treatment.

The following experiments typify the aforementioned 40 aqueous and Thermosol dyeing procedures.

EXPERlMENT l Aqueous (Pressure) Dyeing Procedure Five grams of commercially available polyester fabric were placed in an autoclave containing:

an aqueous dye paste I571 active ingredient) The contents of the autoclave were heated for 1 hour at 265C. The dyed fabric was then rinsed in water and dried. The polyester fabric was dyed an extremely bright, fluorescent red shade.

EXPERIMENT 2 Thermosol Procedure A pad bath was prepared containing:

an aqueous dye paste 1571 active ingredient) containing the dye of Example 5 50 grams purified natural gum thickener 20 grams to l liter water The pad bath was padded on commercially available 65/35 polyester/cotton fabric with a pickup of 50-65%, based on dry fabric weight (owf), followed by drying (infrared predrying followed by hot air or hot can drying is preferable) to remove the water. Thermosoling, by which the polyester component was dyed with the disperse dye, was accomplished by heating the dried pigment-padded fabric for 90 seconds at 213C. Unfixed surface dye, on either the polyester or the cotton or both, was removed by padding the fabric from an aqueous bath containing 50 g./1. of sodium hydroxide and 40 g./l. of sodium hydrosulfite at 2729C., followed by steaming for 30 seconds. The fabric was then rinsed in water at 27C., scoured for minutes at 93C. in water containing 1% ether alcohol sulfate detergent, rinsed in water at 27C. and then dried. After dyeing and cleaning, the material was then padded (for permanent press treatment) with a pickup of 50-65% (owf) with a bath containing:

a dimethyloldihydroxyethyleneurea cross-linking agent 200.0 a p-octylphenoxy(C H O) ,H wetting agent 2.5 a dispersed acrylic thermoplastic binding agent 22.5 a nonionic, paraffin-free, polyethylene emulsion which serves as a fabric softener 22.5 a nonionic polymer emulsion which imparts luster,

a silky hand and antistatic properties to the fiber 30.0 a aqueous zinc nitrate curing catalyst 36.0

EXAMPLE 1 Preparation of Symmetrical Bisanil A mixture of 2.16 parts of diaminomaleonitrile, 9. 16 parts of 4-[N,N-bis(cyanoethyl)amino1benzaldehyde, 0.2 part of p-toluenesulfonic acid, 30 parts of dimethylacetamide (DMAC) and 150 parts of benzene was heated at 8090C. while benzene plus water was removed by distillation. After distillation for 17 hours, the remaining benzene was removed by distillation under nitrogen. After cooling the DMAC solution to 5C. 4.2 parts of red bisanil were collected by filtration; its m.p. was 21 8220C. Thin layer chromatography on silica gel-coated plates using benzene-acetonitrile (4: 1 as eluent showed one scarlet spot at an R, of 0.1.

Calcd. for C H N C, 68.6; H, 5.0; N, 26.5%. Found: C, 68.2; H, 5.4; N, 26.5%.

An infrared spectrum of a Nujol mull of the product showed no NH absorption at 2.8-3.1 ;1.. Based on the above, the product was of the structure p( NCH C NC,,H CH=N-C(CN )#I(CN)N=CHC 4 P 2 4 )2 The mother liquor from the aforesaid filtration was poured into a large volume of ice-cooled water and the precipitated solids were isolated by filtration, washed with water and dried to give 3.9 parts of a red solid,

mp. l85l86C. Thin layer chromatography showed the presence of a minor scarlet spot at an R, of 0.1

and a major yellow spot at an R, of 0.6. The product showed absorption bands at 515 mp. (a,,,,,,, of .10 liters gfcmf) for the bisanil and at 410 mp. (a of 87 1iters gfcmf) for the monoanil formed by hydrolysis 5 of the bisanil during the DMF treatment.

Cald. for C,, ,H .;N C, 68.6; H, 5.0; N, 26.5%.

Found: C, 67.0; H, 5.7; N, 29.5%.

Thus, hydrolysis of the bisanil occurred to provide a mixture comprising a preponderance of the monoanil and a minor amount of the bisanil.

EXAMPLE 2 Preparation of Symmetrical Bisanil A similar result was obtained by starting with the ap- 30 propriate monoanil derivative .instead of diaminomaleonitrile.

EXAMPLE 3 Preparation of Unsymmetrical Bisanil by a Two-Step Process a. A mixture of 132 parts of diaminomaleonitrile, 210 parts of 4-[N,N-bis( ethyl)amino]benzaldehyde, 30 drops of concentrated sulfuric acid and 2,000 parts of tetrahydrofuran (THF) was heated at 65C. for 3 hours. The tetrahydrofuran was partially evaporated and 1,000 parts of ethanol were added. The precipitated solids where isolated by filtration and air dried to give 227 parts of yellow monanil (76% yield). A mixture of 14.1 parts of 4-chlorobenza1dehyde, 20 drops of piperidine and 500 parts of benzene was heated at 80-90C. while continuously azeotroping the water formed during the reaction. The monoanil (13.4 parts) was then added in portions over a 6-hour period and heating at 8090C. was continued for an additional 2 hours. The solvent was removed by distillation and the resultant solid residue was boiled with 200 parts of isopropanol. After filtrationand drying, 9.2 parts (47% yield) of red product were obtained, m.p. 207-208C.

Thin layer chromatography showed the major component to be the unsymmetrical dye along with small amounts of purple impurities. The dye had an absorptivity (a,,,,,, of 177 liters gfcmf at a wavelength (AIIIIIJH) of i i i Calcd. for C H N C1: C, 67.8; H, 5.2; N, 18.0%.

Found: c, 68.6; H, 5.6; N, 17.9%.

Based on the above, the dye was of the structure b. A mixture of 6.7 parts of the monoanil of part (a),

7.05 parts of 4-chlorobenzaldehyde, 0.85 part of piperidine and 250 parts of benzene was heated at 90C. for 1 hour while continuously azeotroping the water formed during the reaction. Thin layer chromatography of the reaction mixture showed the presence of approximately equal amounts of the trans-symmetrical and -unsymrnetrical bisanil dyes; only traces 'of cisbisanil dyes could be detected.

c. When the condensation was run on the same scale but in the presence of only 1 drop of piperidine, the major products after 1 hour at 8090C. were the cissymmetrical and -unsymmetrica1 bisanil dyes. Only traces of trans-bisanil dyes were present.

EXAMPLE 4 Preparation of Unsymmetrical Bisanil by a Four-Step Process A mixture of 21.6 parts of diaminomaleonitrile, 38.3 parts of 4-bromobenzaldehyde, 5 drops of concentrated sulfuric acid and 250 parts of tetrahydrofuran was stirred at 2530C. for 4 hours. Methanol (100 parts) was added and 7.95 parts of sodium borohydride were added in portions over a 20-minute period while maintaining the temperature at 2025C. by external cooling in ice water. After stirring for minutes at 25C. most of the solvent was removed by distillation. The remaining solution was poured into 1,500 parts of ice-cooled water and stirred for 1 hour; the resultant solids were collected and air dried to give 53.5 parts (97% yield) of the reduced monoadduct. This material was used in the next step of the reaction sequence without purification.

A slurry of 53 parts of the reduced monoadduct, 38.8 parts of 4-[N,N-bis(ethyl)amino]benzaldehyde, 1.2 parts of concentrated sulfuric acid and 1,000 parts of ethanol was stirred for 4 hours at -30C. The reaction mixture was filtered and the collected solids were air dried, yielding 83 parts (99% yield) of orange reduced bisadduct. This product was of sufficient purity to use in the next reaction without purification.

A mixture of 82 parts of the reduced bisadduct, 75 parts of manganese dioxide and 500 parts of dimethylformamide was stirred for 4 hours at 2530C. Tetrahydrofuran (500 parts) was added and the resulting mixture was filtered through a medium porosity, sintered glass funnel. The solids thus obtained were washed with four 400-part portions of tetrahydrofuran to dissolve and separate the precipitated bisanil dye from the insoluble manganese oxides. The combined tetrahydrofuran filtrates were concentrated under reduced pressure to a thick slush, 600 parts of isopropanol were added and the resultant slurry was filtered; the collected solids were washed with three 100-part portions of isopropanol to give 61.5 parts (75.6% yield) of bisanil dye, as metallic green flakes, exhibiting an absorptivity (a,,,,,, of 153 liters gf cmf at a wavelength (M of 531 mu. Recrystallization of the product from benzene gave very dark needles, mp. 205206C.; it exhibited an a of 166 liters gfcm7 at a X of 531 mu.

Calcd. for C H N Br: C, 60.8; H, 4.7; N, 16.1%. Found: C, 59.5; H, 4.8; N, 15.6%.

Thin layer chromatographic analysis of the product showed only a single purple spot. Based on the above, the dye was of the structure Preparation of Unsymmetrical Bisanil by a Four-Step Process A mixture of 10.8 parts of diarninomaleonitrile, 15.6 parts of l-naphthaldehyde, 5 drops of concentrated sulfuric acid and 125 parts of tetrahydrofuran was stirred at 2530C. for 17 hours. Methanol (35 parts) was added and the solution was cooled to 15C. Sodium borohydride (3.8 parts) was added in portions while maintaining the temperature between 15-20C. by external water-ice cooling. After stirring for 15 minutes, the solution was poured into 1,500 parts of ice-cooled water and stirred for 3 hours; the solids (the reduced monoadduct as a light tan powder) were removed by filtration.

A slurry of the reduced monoadduct, 18 parts of 4- [N,N-bis(ethyl)amino]benzaldehyde, 15 drops of concentrated sulfuric acid and 200 parts of ethanol was stirred for 17 hours at 2530C. The solids were isolated by filtration, yielding 35.4 parts of the reduced bisadduct as an orange powder.

A mixture of the reduced bisadduct, 35 parts of manganese dioxide and 150 parts of dimethylformamide was stirred for 5 hours at 2530C. The solids were isolated by filtration and washed with four 400-part portions of tetrahydrofuran to give a solution of the desired bisanil dye. The tetrahydrofuran and dimethylformamide were distilled off under reduced pressure and the solids thus obtained were washed with isopropanol and dried, yielding 32.5 parts yield) of bisanil dye as a dark red powder, m.p. 21 1-213C.; it exhibited an absorptivity (a,,,,,, of 183 liters gfcm. at a wavelength (A,,,,,, of 540 mu.

Calcd. for C H N C, 77.0; H, 5.7; N, 17.3%.

Found: C, 76.3; H, 5.6; N, 17.4%.

Thin layer chromatography showed only a single purple spot. Based on the above, the dye was of the structure "N C H5 2 0 EXAMPLE 6 Preparation of Unsymmetrical Bisanil by a Four-Step Process Example 5 was substantially repeated except that another solvent was used in place of tetrahydrofuran in both the reduction and oxidation steps. To a slurry of 12.7 parts of the monoanil of Example 5 in 50 parts of ethyl Cellosolve was added in portions, 0.95 part of sodium borohydride while maintaining the temperature at 25-35C. by external cooling in ice-cooled water. The resulting solution was stirred for 30 minutes, poured into 500 parts of ice water and stirred for 1 additional hour. The light tan precipitate was collected by filtration and air dried to give 12.4 parts yield) of reduced monoadduct.

The reduced monoadduct was condensed with 4- [N,N-bis(ethyl)amino]benzaldehyde in ethanol as described in Example 5 to yield the reduced bisadduct.

A mixture of 5.0 parts of the reduced bisadduct, 5.0 parts of manganese dioxide and 35 parts of dimethylformamide was stirred for 2 hours at 2530C. The solution was poured into 350 parts of icecooled water and 9 parts of concentrated sulfuric acid were added. Hydrogen peroxide (6 parts of a 30% aqueous solution) was added in portions to dissolve the manganese oxides. The resulting mixture was filtered and ,the crude dye thus obtained was washed with two SO-part por tions of isopropanol and dried to give 4.5 parts .(89.4% yield) of the bisanil dye, as a red solid, exhibiting an absorptivity (a,,,,,, of 169 liters gfcm. at a wavelength (X of 540 mu. Thin layer chromatography showed only a si rgle purple spot; the R, was identical to that of the dye of Example 5.

EXAMPLE 7 Preparation of Unsymmetrical Bisanil by a Four-Step Process The dye of Example 4 was also prepared by reaction of the reduced bisadduct (9.6 parts) with 10.6 parts of lead dioxide (0.04 mole) in 200 parts of acetonitrile at 50-55C. for 9 hours. The suspended lead sludge was filtered off and the solvent was evaporated. Thin layer chromatography showed the residue to consist of approximately equal amounts of the unsymmetrical bisanil dye of Example 4 and the colorless isomeric imidazole. The imidazole was removed by prolonged extraction of the solid with hot (8090C.) ethanol; the extracted product was shown by thin layer chromatography to consist of a single purple spot. The analytical data obtained on the product was substantially the same as that reported in Example 4.

EXAMPLE 8 Preparation of Symmetrical Bisanil A mixture of 9.4 parts of 4-[N,N-bis(ethyl)amino]- benzaldehyde, 2.16 parts of diaminomaleonitrile, 4.0 parts of phosphorus pentoxide, 6 drops of concentrated sulfuric acid and 70 parts of hexamethylphosphoramide was stirred at 5055C. for 6 hours. After each 2-hour period, an additional 1.0 part of phosphorus pentoxide was added. The reaction mixture was then poured into 800 parts of water containing 20 parts of aqueous ammonium hydroxide. After stirring for 1 hour, the precipitated solids were collected by filtration, washed with water and dried to yield 5.5 parts (65% yield) of symmetrical bluish-red bisanil, m.p. 140142C. The product was recrystallized three times from isopropanol, providing an analytically pure sample, m.p. l62-l 65C. The product exhibited a high intensity absorption band (105 liters gfcmf) at a wavelength of 558 mu and, in addition, two lower intensity bands at 400 mp. (61.5 liters gfcmf') and 382 mp. (56 liters g. cm. Based on the presence of the lower wavelength absorption bands and the large observed dipole moment of 14.6 Debye, the product was confirmed as having cis geometry about the central carbon-carbon double bond. Based on the above, the

structure is EXAMPLE 9 Preparation of Symmetrical Bisanil A mixture of 10.8 parts of diaminomaleonitrile, 29.0

parts of indole-3-carboxaldehyde, 400 parts of tetrahysodium carbonate were added. The precipitated solids LII A mixture of 14.1 parts of the monoanil, 12.0 parts of concentrated sulfuric acid, 11.6 parts of indole-3-carboxaldehyde and parts of dimethylformamide was heated in about 10 minutes to l45l50C.; it was maintained at this temperature for 20 minutes. The reaction mixture was then poured into 1,000 parts of water. The precipitated solids were collected by filtration, washed with water, then with isopropanol and dried. The product was recrystallized three times from acetonitrile-chloroform to give 6.85 parts (31.7% yield) of the symmetrical yellow bisanil, m.p. 331333C. The dye had an absorptivity (a,,,,, of 220 liters gfcmf at a wavelength (X of 480 mu.

Calcd. for C I-I N C, 72.9; H, 3.9; N, 23.2%. Found: C, 71.4; H, 4.3; N, 22.3%.

Based on the above, the structure of the dye is EXAMPLE 10 Preparation of Unsymmetrical Bisanil A mixture of 4.7 parts of indole-3-carboxaldehydediaminomaleonitrile monoanil, 3.54 parts of 4- [N,N-bis( ethyl)amino]benzaldehyde, 4.0 parts of concentrated sulfuric acid and 50 parts of dimethylformamide was heated at l45l50C. for 20 minutes. The reaction mixture was then poured into 1,000 parts of water. The precipitated solids were filtered off, washed with water and dried. Thin layer chromatographic analysis showed the presence of the two possible symmetrical bisanil condensates, together with a third bright reddish-orange component. The latter material was isolated from the product mixture by column chromatography on Florisil using chloroform as eluent. After two recrystallizations from acetonitrile, a small amount (0.10 part) of the pure unsymmetrical bisanil condensate was obtained, m.p. 265268C. Infrared analysis showed an NH band at 3395 cm. and CN absorption at 2200 cm. and 660 emf. The visible absorption spectrum exhibited ak of 522 mp. and an a,,,,,, of 239 liters gfcmf. Based on the above, the structure of the dye is EXAMPLE 11 Preparation of Symmetrical Bisanil A mixture of 2.16 parts of diaminomaleonitrile, 3.5 parts of 4-[N,N-bis(ethyl)aminoJbenzaldehyde, 8.0 parts of concentrated sulfuric acid and 50 parts of dimethylformamide was stirred at l45l50C. for 20 minutes. The reaction mixture was then poured into 1,000 parts of water; the precipitated solids were collected by filtration, washed with water and dried. The

product was purified by column chromatography on Florisil using chloroform as eluent, yielding 0.47 part of bluish-red bisanil,'m.p. 265-268C. [t exhibited an absorptivity (a,,,,,, of 265 liters gfcm at a wavelength of 561 mu. A nuclear magnetic resonance (NMR) spectrum of the product was found to be identical to that of the dye of Example 8. However, the absence of any lower wavelength absorption, together with the much higher melting point and a low observed dipole moment of 3.2 Debye indicates that the product is ac- 26 (3')( )X c1i=11-c(ci1)=c(c11)-N=cn (L1) 5 (6') A z 5) Y tually the trans form of the dye of Example 8.

The isomerization of the cis dye of Example 8 to the trans fonn of this example was readily effected by heating the former dye in benzene containing a small amount of iodine. The resultant product was identical in m.p. and spectral properties to the trans isomer.

EXAMPLES 12-1 1 8 Y Symmetrical bisanil dyes were prepared (Examples 12-19) by procedures similar to that described in Example 2. Unsymmetrical bisanil dyes were prepared (Examples 20-118) by preferred four-step processes The groups shown in column Y for Examples 34, 39,

82, 87, 88 and 95 correspond to the entire group similar to those described in Examples 4 and 5.'Data A for the dyes produced are shown in Table 11. Except as 20 noted below the substituents A, B, C, X, Y and Z appearing as column headings in the table correspond to B the substituents shown in the formula c TABLE 11 Example NO. A B C y X Y 7 z 12 H H H H H H 13 H (4')-N(n- H H (4)-N(n-C ,H,) H

' n 7)-z 4 H 4' -oCH, H H (4 )-OCH;, H 15 (2' -oCH (4' )-OCH,, H (2 -0CH,, (4 )-OCH H 16 H 2 .s) H H (4)-N(C2H5)C2H-1CN H 2! l7 (2' )-CH 1 (4' )-N(C2H5)- H )'CH:1 (4)'N( C2"; )C2H4CN H.

C H,CN 18 (-0 (41-14mm). H (2) 1 (4)-N( H-.)-. H 19 H 40. )-N(CH H H (4 -N CH C,,H,CO H

c,H.co,cH,, 3 20 H H H H 4 )-N(CH,-,)C2H ,CN H 21 H (4' )-Cl H H 4 -N CH, C H,CN H

Elemental Analysis Example A max. max. Shade on Calculated Found No. (my). (l.g."cm.") Polyester C H N C H N 12 432 yellow 58.4 7.4 34.2 57.9 6.8 34.5 561 205 Bluish 74.5 7.9 17.6 73.6 7.2 17.7 13

Red 14 427 159 Greenish 69.8 4.7 16.3 69.3 4.8 15.1

Yellow 1 5 460 170 Yellow 16 540 215 Red 70.6 5.9 23.5 70.2 6.0 22.6 17 550 171 Bluish 71.4 6.4 22.5 71.7 6.7 21.9

Red 111 555 223 Bluish 60.2 4.6 19.1 60.3 4.7 19.5

Red 19 543 194 Red 65.4 5.9 16.3 64.2 5.4 16.0 20 500 141 Bright 72.1 4.9 22.9 72.0 4.9 22.9

Orange 21 510 168 Orange 65.9 4.2 21.0 64.7 4.1 21.2

Example N0. A B C X Y z 22 (2)-C1 H (6' )-Cl H 4 -N(CH C H,CN H 23 2' -N0 H H H (4)-N(CH.1)C H,CN H 24 H 4' -NO H H (4)-N( =1) 2 4 H 25 H H H H (4)-N(C2H.1)2 H 26 -H H H (2)-OH (4)-N(C2H5)2 H 27 2-furyl H (4 )-1 1 C.,H )2 H 28 (2)-0H H H H (4 -N C H,, H 29 H H H (2)-CH (4)-N(C2H,,)C2H,CN H 30 H H H H (4)-N(C2H4CN)2 H 31 2-furyl v H (4)-N C,H,CN C.,H,- H

TABLE ll-continued Elemental Analysis Example A max. max. Shudeon Calculated Found No. (my) (l.g.em. Polyester H N C H N 22 514 135 Orange 606 3.7 19.3 61.0 3.6 18.9 23 512 115 Orange 64.1 4.1 23.8 63.5 4.0 22.7 24 530 135 Bright 64.2 4. 23.8 63.4 4.4 22.3

Red 3 l 25 525 195 Red' -'74.3 6.0 19.7' g 74.5 6.2 19.5 26 527 176 Bright 71.2 5.7 18.8 66.8 5.2 17.1

Red 27 530 208 Red 69.6 5.5 20.3 68.5 5.1 19.6' 28 531 186 Bright 71.1 5.7 19.0 67.8 6.2 176' Red I 29 510 138 Bright 73.1 5.6 21.3 69.9 5.0 19.9

Orange 30 488 152 Yellow 71.0 4.7 24.3 72.5 4.7 24.2 31 500 118 Orange- 68.5 4.5 17:1 67.8 4.1 16.9

Example 7 1 No. A B C X Y 6 Z 32 (2')-NO H H H (4)-N(C H H 33 (2)-Cl H (6'10 H (C2 5) H 34 H H H I 4-N,N-dimethylarninp- 1 -naphthyl 35 H 4' )-NO. H H 9 (4 )-N( 2 5 )2. H 36 H H H (2)-CH (4) N(C H,-,)CH H H CH OC H OCONHC H 37 H (4' )-Cl H H 2 5) 2 -r H OCOC.,H 38 (2' )-Cl H H H 2 .s)2 H 39 (2')-Cl H (6')-C1 3-ind0ly1 40 H (3')-C1 H (2)-CH,-, (4)-N(C H )C H CN H 41 H (4 )-Cl H ('2 )-CH';, (4 )-N( C H ,)C H. CN H Elemental Analysis Example 1\ max. max. Shade 011' Calculated Found No. (my) 1 .g."cm.' Polyester C H C H N 32 542 150 Violet 66.0 5.1 21.0 64.4 5.2 20.5 33 540 145 Bright 62.3 4.5 16.5 61.5 4.7 15.7

Bluish Red v 34 560 133 Bluish 76.4 5.1 18.6 74.6 5.8 19.3

Red l 35 560 1 18 Violet 66.0 5.0 21.0 66.9 5.7 17.8 36 520 92 Bright 72.8 5.6 13.8 69.0 5.9 l 1.7

Orange 37 520 107 Bright 7 68.1 4.7 13.7 67.9 4.6 12.9

Orange 38 540 124 Bright 67.8 5.2 18.0 67.2 5.0 1 7.3 Bluish Red v 39 460 121 Reddish 61.3 2.8 17.8 59.8 2.7 18.5

Yellow 3 40 523 154 Bright 67.2 6.0 19 .6 67.3 5.2 19.2

Orange I 41 520 153 Bright 67.2 6.0 19.6 67.2 5.1 19.4

Example l A B C X Y Z No. I

42 H (3')-C1 H H (4)-N(C H H 43 (2')-Cl H H H (4)-N(C H,,) H 44 H H H (4)'N(CH:I)2 H 45 H (4')-Cl H (2)-Cl (4)-N(Cl-l H 46 (3' )-cl 4' 0 H H (4)-N(C-. .)2 H 47 (3)-C1 (4')-c| H (2)-CH.-, (4)-N 5 2 H 48 2')-c| (en-N0 H H (4)-N 2 H 49 l-naphthyl (2 )-CH,, (4 )-N(C H,,)C H CN H 50 l-naphthyl H (4 )-N(CH CH,CH CH,,)

Elemental Analysis Example A max. max. Shade 0n Calculated Found No. (my) (1.g."cm.") Polyester C H C H N 42 533 152 Bright 67.8 5.2 18.0 I 68.0 5.3 17.4

Red r l 43 540 118 Bright 67.8 5.2 18.0 68.0 5.5 17.4

Red 44 510 Orange 66.4 4.5 19.3 64.7 5.1 17.1 45 519 148 Orange 61.1 3.8 17.6 61.2 5.4 12.1 46 540 157 Bright 62.2 4.5 16.5 60.7 4.6 15.6

Bluish Red 7 47 518 162 Scarlet 48 550 139 Violet 1.8 4.4 19.3 60.9 4.4 19.1 49 527 158 Scarlet" I 75.4 5.4 18.9 76.2 5.8 17.8 50 540 146 78.1 6.8 15.2 77.7 6.7 14.8

Red

TABLE ll-continued Example 0. A B C X Y Z 109 H (4')-NHCOCH;, H (2)-CH (4)N(C H H 1 H (4')-NHCOCH;, H H (4)N(CH CH-,CH, H l l l H (4')-NHCOC2H5 H 3 2 :s)-z H 1 12 H (4')-NHCOC H5 H H a) 2 4 2 a H 1 13 H (4')-OCH;; H 3 (4) "N(C2H5)C2H4CO2CH:1 H l 14 H (2')-Cl H H (4)N(CH )C H CO CH H 1 15 H (2' )-Cl H (2 )-CH (4)--N(C H,,)C H CO CH H l 16 H (2') Cl H (2)-CH (4)-N(C H )CH HCH OC H H OCONHC,,H,, l 17 (3' )-Cl (4')-C1 H (4)N(CH,-,)C H CO CH H 18 3-(N-methyl)indolyl H (4)-N(C H,,)., H

Elemental Analysis Example A max. max. Shade on Calculated Found No. (my) 1 .gfcmf) Polyester C H N C H N 109 532 171 Red 70.4 6.1 19.7 71.3 6.8 21.0 1 10 527 174 Red 70.9 6.4 19.1 70.5 6.2 19.4 1 l 1 532 139 Red 70.4 6.1 19.7 70.5 6.7 19.4 112 s 510 122 Orange 66.4 5.5 17.9 66.0 5.2 17.7 1 13 518 150 Scarlet 68.3 5.9 15.3 67.9 6.4 16.2 1 14 520 131 Scarlet 63.9 4.4 16.2 65.2 4.5 15.8 115 532 129 Red 65.1 5.2 15.2 64.4 4.9 16.3 1 16 530 78 Red 117 519 152 Scarlet 59.0 4.1 15.0 57.3 3.7 17.1 118 525 215 Scarlet 73.5 5.9 20.6 70.4 5.2 19.1

I claim: same as or different from the aldehyde of step 1 1. Improved process of preparing the bisanil dye of the formula Ar CH=N-C(CN)=C(CN)N=A CHAr wherein each of Ar. and Ar is independently selected from phenyl and naphthyl groups containing 0-3 substituents selected from N0 halogen, CN, C alkyl, C alkoxy, OCH -phenyl, phenyl, CF OH, 0C alkylene-N(C alkyl) C alkylene-Cl NHCONH NHCOA, NHSO A, SR,,, 80 R NHR NHCOC alkylene-B and -NR R wherein: a. R is C alkyl or C alkylene-R b. R is C,-., alkyl, C alkylene-R or, if Ar or Ar is phenyl, C alkylene attached to a phenyl position which is ortho to the position to which the nitrogen is attached;

c. R,-, is CN, halogen, OH, phenyl, C alkoxy, OC alkylene-CN, CO A, OCOA, OCONHA or CO C, alkylene-OCOA:

d. R, is CN, halogen, OH, phenyl, OC alkylene- CN, CO A, OCOA, CO C alkylene-OCOA, 80 A, phthalimido, succinimido, glutarimide, OCOCH=CH CH CH(OCOA)CH OA or CH CH(OCONHA)CH OA:

e. A is C,-., alkyl or R f. B is halogen, C alkoxy or R g. R is phenyl containing 0-2 substituents selected from C,, alkyl, C alkoxy, halogen, N0 CN, C, alkyl-CONH and NR R wherein each of R and R is independently selected from H and C alkyl, with at least one of R and R being C alkyl; and

h. R. is c,-,, alkyl, C H OH, c cycloalkyl or R said bisanil dye being substantially free of imidazole impurities, whichvprocess comprises the steps:

l. condensing .diaminomaleonitrile and the aromatic aldehyde Ar CHO to produce the monoanil Ar- ,-CH=NC(CN)=C(CN)-NH 2. reducing the monoanil from step (1) to produce Ar CH NHC(CN)=C(CN)-NH 3. condensing the product from step (2) and the aromatic aldehyde Ar CHO, which aldehyde is the to produce the monoanil Ar CH N- 4. oxidizing the monoanil from step (3) with manganese dioxide, at ambient temperature, in the presence of a solvent selected from the group consisting of dimethylformamide, dimethylacetamide, di-

methylsulfoxide, hexamethylphosphoramide and N-methylpyrrolidone to produce the bisanil dye Ar C1-FN-C(CN)=C(CN)N=CH--Ar 2. Process of claim 1 wherein in step (4) the solvent is dimethylformamide, the temperature is 2530C. and the reaction time is about 4 hours.

3. Process of claim 2 wherein Ar and Ar are the same.

4. Process of claim 2 wherein Ar and Ar are differem.

5. Process of claim 2 wherein the reducing agent employed in step (2) is sodium borohydride.

6. Process of claim 2 wherein step 1 is carried out in the presence of an organic solvent other than a ketone or aldehyde which can react with diaminomaleonitrile, at a temperature of 2080C., for 4-17 hours; step (2) is carried out in the presence of an organic solvent, at a temperature not in excess of 35C., with at least 0.50 mole of reducing agent per mole of monoanil; and step (3) is carried out in the presence of an organic solvent.

7. Process of claim 6 wherein an acid catalyst is employed in steps 1) and (3) and the temperature in step (2) is 10-35C.

8. Process of claim 7 wherein in steps (1) and (3) the solvent is selected from tetrahydrofuran, ethyl Cellosolve, dimethylformamide, methanol, ethanol and mixtures thereof, the acid catalyst is selected from sulfuric acid, hydrochloric acid, p-toluenesulfonic acid and trifluoroacetic acid and the temperature is 25-30C.; and in step (2) the solvent is selected from tetrahydrofuran, methanol, ethanol and ethyl Cellosolve and the temperature is less than 25C.

9. Process of claim 8 wherein the solvent in step (2) is methanol or ethanol.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,912,724 D TED October 14, 1975 INV N 1 Robert Walter Begland It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 33, line 27, at the end of the line, "A" should be deleted.

a Signed and Scaled this ninth a O L] D y f Mareh1976 Arrest:

RUTH c. M A SoN c. MARSHALL DANN Altestmg Ojflcer (mnmisxiuner oj'Parents and Trademarks 

1. IMPROVED PROCESS OF PREPARING THE BISANIL DYE OF THE FORMULA AR1-CH=N-C(CH)VC(CN)-N=CH-AR. WHEREIN EACH OF AR1 AND AR2 IS INDEPENDENTLY SELECTED FROM PHENYL AND NAPHTHYL GROUPS CONTAING 0-3 SUBSTITUENTS SELECT FROM NO2, HAOGEN, CN,C1-4ALKYL, C1-4ALKOXY, OCH2-PHENYL, PHE ALKYL)2, C2-4 ALKYLENE-CL, NHCONH2, NHCA, NHSO2A, SR8, SO2R8, NHR1, NHCOC1-4 ALKYLENE-B AND -NR1R2 WHEREIN: A. R1 IS C1-4 ALKYL OR C2-4 ALKYLENE-R3, B. R2IS C1-4 ALKYL, C2-4 ALKYLENE-R4, OR, IF AR1 OR AR2 IS PHENYL, C3 ALKYLENE ATTACHED TO A PHENYL POSITION WHICH IS ORTHO TO THE POSITION TO WHICH THE NITROGEN IS ATTACHED, C. R3 IS CN, HALOGEN, OH, PHENYL, C1-4 ALKYLENE-CN1-4 ALKYLENE-CN, CO2A, OCOA, OCONHA OR CO2C1-4 ALKYLENE-OCOA: D. R4 IS CN, HALOGEN, OH, PHENYL, OC1-4 ALKYLENE-CN, CO2A, OCOA, CO2C1-4 ALKYLENE-OCOA, SO2A, PHTHALIMIDO, SUCCINIMIDO, GLUTARIMIDE, OCOCH=CH2, CH2-CH(OCOA)CH2OA OR CH2CH(OCONHA)CH2OA: E. A IS C1-4 ALKYL OR R5, F. B IS HALOGEN, C1-4 ALKOXY OR R5, G. R5 IS PHENYL CONTAINING 0-2 SUBSTITUENTS SELECTED FORM C1-4 ALKYL, C1-4 ALKOXY, HALOGEN, NO2, CN, C1-4 ALKYLCONH AND NR6R7 WHEREIN EACH OF R6 AND R7 IS INDEPENDENTLY SELECTED FROM H AND C1-4 ALKYL, WITH AT LEAST ONE OF R6 AND R7 BEING C1-4 ALKYL, AND H. R8 IS C1-4 ALKYL, C2H4OH, C5-6 CYCLOALKYL OR R5, SAID BISANIL DYE BEING SUBSTANTIALLY FREE OF IMIDAZOLE IMPURITIES, WHICH PROCESS COMPRISES THE STEPS:
 1. CONDENSING DIAMINOMALEONITRILE AND THE AROMATIC ALDEHYDE AR1CHO TO PRODUCE THE MONOANIL AR1-CH=NC(CN)=C(CN)-NH2,
 2. REDUCING THE MONOANIL FORM STEP (1) TO PRODUCE AR1CH2NH-C(CN=C(CN)-NH2,
 2. reducing the monoanil from step (1) to produce Ar1CH2NH-C(CN) C(CN)-NH2;
 2. Process of claim 1 wherein in step (4) the solvent is dimethylformamide, the temperature is 25*-30*C. and the reaction time is about 4 hours.
 3. Process of claim 2 wherein Ar1 and Ar2 are the same.
 3. condensing the product from step (2) and the aromatic aldehyde Ar2CHO, which aldehyde is the same as or different from the aldehyde of step (1), to produce the monoanil Ar1CH2NH-C(CN) C(CN)-N CH-Ar2; and
 3. CONDENSING THE PRODUCT FROM STEP (2) AND THE AROMATIC ALDEHYDE AR2CHO, WHICH ALDEHYDE IS THE SAME AS OR DIFFERENT FROM THE ALDEHYDE OF STEP (1), TO PRODUCE MONOANIL AR1CH2NH-C(CN)=C(CN)-N=CH-AR2, AND
 4. OXIDIZING THE MONOANIL FROM STEP (3) WITH MANGANESE DIOXIDE, AT AMBIENT TEMPERATURE, IN THE PRESENCE OF A SOLVET SELECTED FROM THE GROUP CONSISTING OF DIMETHYLFORMAMIDE, DIMTHYLACETAMIDE, DIMETHYLUSULFOXIDE, HEXAMETHYLPHOSPHORAMIDE AND N-METHYLPYRROLIDONE TO PRODUCE THE BISANIL DYE AR1-CH=N-C(CN)=C(CN)-N= CH-AR2.
 4. oxidizing the monoanil from step (3) with manganese dioxide, at ambient temperature, in the presence of a solvent selected from the group consisting of dimethylformamide, dimethylacetamide, dimethylsulfoxide, hexamethylphosphoramide and N-methylpyrrolidone to produce the bisanil dye Ar1-CH N-C(CN) C(CN)-N CH-Ar2.
 4. Process of claim 2 wherein Ar1 and Ar2 are different.
 5. Process of claim 2 wherein the reducing agent employed in step (2) is sodium borohydride.
 6. Process of claim 2 wherein step (1) is carried out in the presence of an organic solvent other than a ketone or aldehyde which can react with diaminomaleonitrile, at a temperature of 20*-80*C., for 4-17 hours; step (2) is carried out in the presence of an organic solvent, at a temperature not in excess of 35*C., with at least 0.50 mole of reducing agent per mole of monoanil; and step (3) is carried out in the presence of an organic solvent.
 7. Process of claim 6 wherein an acid catalyst is employed in steps (1) and (3) and the temperature in step (2) is 10*-35*C.
 8. Process of claim 7 wherein in steps (1) and (3) the solvent is selected from tetrahydrofuran, ethyl Cellosolve, dimethylformamide, methanol, ethanol and mixtures thereof, the acid catalyst is selected from sulfuric acid, hydrochloric acid, p-toluenesulfonic acid and trifluoroacetic acid and the temperature is 25*-30*C.; and in step (2) the solvent is selected from tetrahydrofuran, methanol, ethanol and ethyl Cellosolve and the temperature is less than 25*C.
 9. Process of claim 8 wherein the solvent in step (2) is methanol or ethanol. 